In the closest anyone at Milan has to come to saying the Brazilian is leaving, Galliani told Thursday's Gazzetta dello Sport that the club had little option.
"The reasons for the departure of Kaka are solely economic," he said. "Even a great heart must confront the situation and make choices. Milan cannot go on losing 70 million euro a year."
Hundreds of Milan fans gathered outside the club's city centre offices on Thursday to protest against the possible sale.
Banners included one which read: "If you sell Kaka, sell the club".
Reports have also linked the Premier League club with Milan's Alexandre Pato and Andrea Pirlo, but Galliani was adamant they were not leaving.
"We're not falling apart. The other big players are not for sale. Now a great attacker will arrive," he said.
"In January, Kaka didn't want to go to Manchester City," Galliani added. "Instead he would go to Madrid."
